/*
 * Copyright (c) 2007-2012, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: XPath.java,v 1.2.4.1 2005/09/15 01:41:57 jeffsuttor Exp $
 */
package com.sun.org.apache.xpath.internal;

import java.io.Serializable;

import javax.xml.transform.ErrorListener;
import javax.xml.transform.SourceLocator;
import javax.xml.transform.TransformerException;

import com.sun.org.apache.xalan.internal.res.XSLMessages;
import com.sun.org.apache.xml.internal.dtm.DTM;
import com.sun.org.apache.xml.internal.utils.PrefixResolver;
import com.sun.org.apache.xml.internal.utils.SAXSourceLocator;
import com.sun.org.apache.xpath.internal.compiler.Compiler;
import com.sun.org.apache.xpath.internal.compiler.FunctionTable;
import com.sun.org.apache.xpath.internal.compiler.XPathParser;
import com.sun.org.apache.xpath.internal.functions.Function;
import com.sun.org.apache.xpath.internal.objects.XObject;
import com.sun.org.apache.xpath.internal.res.XPATHErrorResources;

/**
 * The XPath class wraps an expression object and provides general services
 * for execution of that expression.
 * @xsl.usage advanced
 */
public class XPath implements Serializable, ExpressionOwner {
    static final long serialVersionUID = 3976493477939110553L;

    /** The top of the expression tree.
     *  @serial */
    private Expression m_mainExp;

    /**
     * The function table for xpath build-in functions
     */
    private transient FunctionTable m_funcTable = null;

    /**
     * initial the function table
     */
    private void initFunctionTable() {
        m_funcTable = new FunctionTable();
    }

    /**
     * Get the raw Expression object that this class wraps.
     *
     *
     * @return the raw Expression object, which should not normally be null.
     */
    public Expression getExpression() {
        return m_mainExp;
    }

    /**
     * This function is used to fixup variables from QNames to stack frame
     * indexes at stylesheet build time.
     * @param vars List of QNames that correspond to variables.  This list
     * should be searched backwards for the first qualified name that
     * corresponds to the variable reference qname.  The position of the
     * QName in the vector from the start of the vector will be its position
     * in the stack frame (but variables above the globalsTop value will need
     * to be offset to the current stack frame).
     */
    public void fixupVariables(java.util.Vector vars, int globalsSize) {
        m_mainExp.fixupVariables(vars, globalsSize);
    }

    /**
     * Set the raw expression object for this object.
     *
     *
     * @param exp the raw Expression object, which should not normally be null.
     */
    public void setExpression(Expression exp) {
        if (null != m_mainExp)
            exp.exprSetParent(m_mainExp.exprGetParent()); // a bit bogus
        m_mainExp = exp;
    }

    /**
     * Get the SourceLocator on the expression object.
     *
     *
     * @return the SourceLocator on the expression object, which may be null.
     */
    public SourceLocator getLocator() {
        return m_mainExp;
    }

    //  /**
    //   * Set the SourceLocator on the expression object.
    //   *
    //   *
    //   * @param l the SourceLocator on the expression object, which may be null.
    //   */
    //  public void setLocator(SourceLocator l)
    //  {
    //    // Note potential hazards -- l may not be serializable, or may be changed
    //      // after being assigned here.
    //    m_mainExp.setSourceLocator(l);
    //  }

    /** The pattern string, mainly kept around for diagnostic purposes.
     *  @serial  */
    String m_patternString;

    /**
     * Return the XPath string associated with this object.
     *
     *
     * @return the XPath string associated with this object.
     */
    public String getPatternString() {
        return m_patternString;
    }

    /** Represents a select type expression. */
    public static final int SELECT = 0;

    /** Represents a match type expression.  */
    public static final int MATCH = 1;

    /**
     * Construct an XPath object.
     *
     * (Needs review -sc) This method initializes an XPathParser/
     * Compiler and compiles the expression.
     * @param exprString The XPath expression.
     * @param locator The location of the expression, may be null.
     * @param prefixResolver A prefix resolver to use to resolve prefixes to
     *                       namespace URIs.
     * @param type one of {@link #SELECT} or {@link #MATCH}.
     * @param errorListener The error listener, or null if default should be used.
     *
     * @throws javax.xml.transform.TransformerException if syntax or other error.
     */
    public XPath(String exprString, SourceLocator locator, PrefixResolver prefixResolver, int type, ErrorListener errorListener) throws javax.xml.transform.TransformerException {
        initFunctionTable();
        if (null == errorListener)
            errorListener = new com.sun.org.apache.xml.internal.utils.DefaultErrorHandler();

        m_patternString = exprString;

        XPathParser parser = new XPathParser(errorListener, locator);
        Compiler compiler = new Compiler(errorListener, locator, m_funcTable);

        if (SELECT == type)
            parser.initXPath(compiler, exprString, prefixResolver);
        else if (MATCH == type)
            parser.initMatchPattern(compiler, exprString, prefixResolver);
        else
            throw new RuntimeException(XSLMessages.createXPATHMessage(XPATHErrorResources.ER_CANNOT_DEAL_XPATH_TYPE, new Object[] { Integer.toString(type) })); //"Can not deal with XPath type: " + type);

        // System.out.println("----------------");
        Expression expr = compiler.compile(0);

        // System.out.println("expr: "+expr);
        this.setExpression(expr);

        if ((null != locator) && locator instanceof ExpressionNode) {
            expr.exprSetParent((ExpressionNode) locator);
        }

    }

    /**
     * Construct an XPath object.
     *
     * (Needs review -sc) This method initializes an XPathParser/
     * Compiler and compiles the expression.
     * @param exprString The XPath expression.
     * @param locator The location of the expression, may be null.
     * @param prefixResolver A prefix resolver to use to resolve prefixes to
     *                       namespace URIs.
     * @param type one of {@link #SELECT} or {@link #MATCH}.
     * @param errorListener The error listener, or null if default should be used.
     *
     * @throws javax.xml.transform.TransformerException if syntax or other error.
     */
    public XPath(String exprString, SourceLocator locator, PrefixResolver prefixResolver, int type, ErrorListener errorListener, FunctionTable aTable) throws javax.xml.transform.TransformerException {
        m_funcTable = aTable;
        if (null == errorListener)
            errorListener = new com.sun.org.apache.xml.internal.utils.DefaultErrorHandler();

        m_patternString = exprString;

        XPathParser parser = new XPathParser(errorListener, locator);
        Compiler compiler = new Compiler(errorListener, locator, m_funcTable);

        if (SELECT == type)
            parser.initXPath(compiler, exprString, prefixResolver);
        else if (MATCH == type)
            parser.initMatchPattern(compiler, exprString, prefixResolver);
        else
            throw new RuntimeException(XSLMessages.createXPATHMessage(XPATHErrorResources.ER_CANNOT_DEAL_XPATH_TYPE, new Object[] { Integer.toString(type) }));
        //"Can not deal with XPath type: " + type);

        // System.out.println("----------------");
        Expression expr = compiler.compile(0);

        // System.out.println("expr: "+expr);
        this.setExpression(expr);

        if ((null != locator) && locator instanceof ExpressionNode) {
            expr.exprSetParent((ExpressionNode) locator);
        }

    }

    /**
     * Construct an XPath object.
     *
     * (Needs review -sc) This method initializes an XPathParser/
     * Compiler and compiles the expression.
     * @param exprString The XPath expression.
     * @param locator The location of the expression, may be null.
     * @param prefixResolver A prefix resolver to use to resolve prefixes to
     *                       namespace URIs.
     * @param type one of {@link #SELECT} or {@link #MATCH}.
     *
     * @throws javax.xml.transform.TransformerException if syntax or other error.
     */
    public XPath(String exprString, SourceLocator locator, PrefixResolver prefixResolver, int type) throws javax.xml.transform.TransformerException {
        this(exprString, locator, prefixResolver, type, null);
    }

    /**
     * Construct an XPath object.
     *
     * @param expr The Expression object.
     *
     * @throws javax.xml.transform.TransformerException if syntax or other error.
     */
    public XPath(Expression expr) {
        this.setExpression(expr);
        initFunctionTable();
    }

    /**
     * Given an expression and a context, evaluate the XPath
     * and return the result.
     *
     * @param xctxt The execution context.
     * @param contextNode The node that "." expresses.
     * @param namespaceContext The context in which namespaces in the
     * XPath are supposed to be expanded.
     *
     * @return The result of the XPath or null if callbacks are used.
     * @throws TransformerException thrown if
     * the error condition is severe enough to halt processing.
     *
     * @throws javax.xml.transform.TransformerException
     * @xsl.usage experimental
     */
    public XObject execute(XPathContext xctxt, org.w3c.dom.Node contextNode, PrefixResolver namespaceContext) throws javax.xml.transform.TransformerException {
        return execute(xctxt, xctxt.getDTMHandleFromNode(contextNode), namespaceContext);
    }

    /**
     * Given an expression and a context, evaluate the XPath
     * and return the result.
     *
     * @param xctxt The execution context.
     * @param contextNode The node that "." expresses.
     * @param namespaceContext The context in which namespaces in the
     * XPath are supposed to be expanded.
     *
     * @throws TransformerException thrown if the active ProblemListener decides
     * the error condition is severe enough to halt processing.
     *
     * @throws javax.xml.transform.TransformerException
     * @xsl.usage experimental
     */
    public XObject execute(XPathContext xctxt, int contextNode, PrefixResolver namespaceContext) throws javax.xml.transform.TransformerException {

        xctxt.pushNamespaceContext(namespaceContext);

        xctxt.pushCurrentNodeAndExpression(contextNode, contextNode);

        XObject xobj = null;

        try {
            xobj = m_mainExp.execute(xctxt);
        } catch (TransformerException te) {
            te.setLocator(this.getLocator());
            ErrorListener el = xctxt.getErrorListener();
            if (null != el) // defensive, should never happen.
            {
                el.error(te);
            } else
                throw te;
        } catch (Exception e) {
            while (e instanceof com.sun.org.apache.xml.internal.utils.WrappedRuntimeException) {
                e = ((com.sun.org.apache.xml.internal.utils.WrappedRuntimeException) e).getException();
            }
            // e.printStackTrace();

            String msg = e.getMessage();

            if (msg == null || msg.length() == 0) {
                msg = XSLMessages.createXPATHMessage(XPATHErrorResources.ER_XPATH_ERROR, null);

            }
            TransformerException te = new TransformerException(msg, getLocator(), e);
            ErrorListener el = xctxt.getErrorListener();
            // te.printStackTrace();
            if (null != el) // defensive, should never happen.
            {
                el.fatalError(te);
            } else
                throw te;
        } finally {
            xctxt.popNamespaceContext();

            xctxt.popCurrentNodeAndExpression();
        }

        return xobj;
    }

    /**
     * Given an expression and a context, evaluate the XPath
     * and return the result.
     *
     * @param xctxt The execution context.
     * @param contextNode The node that "." expresses.
     * @param namespaceContext The context in which namespaces in the
     * XPath are supposed to be expanded.
     *
     * @throws TransformerException thrown if the active ProblemListener decides
     * the error condition is severe enough to halt processing.
     *
     * @throws javax.xml.transform.TransformerException
     * @xsl.usage experimental
     */
    public boolean bool(XPathContext xctxt, int contextNode, PrefixResolver namespaceContext) throws javax.xml.transform.TransformerException {

        xctxt.pushNamespaceContext(namespaceContext);

        xctxt.pushCurrentNodeAndExpression(contextNode, contextNode);

        try {
            return m_mainExp.bool(xctxt);
        } catch (TransformerException te) {
            te.setLocator(this.getLocator());
            ErrorListener el = xctxt.getErrorListener();
            if (null != el) // defensive, should never happen.
            {
                el.error(te);
            } else
                throw te;
        } catch (Exception e) {
            while (e instanceof com.sun.org.apache.xml.internal.utils.WrappedRuntimeException) {
                e = ((com.sun.org.apache.xml.internal.utils.WrappedRuntimeException) e).getException();
            }
            // e.printStackTrace();

            String msg = e.getMessage();

            if (msg == null || msg.length() == 0) {
                msg = XSLMessages.createXPATHMessage(XPATHErrorResources.ER_XPATH_ERROR, null);

            }

            TransformerException te = new TransformerException(msg, getLocator(), e);
            ErrorListener el = xctxt.getErrorListener();
            // te.printStackTrace();
            if (null != el) // defensive, should never happen.
            {
                el.fatalError(te);
            } else
                throw te;
        } finally {
            xctxt.popNamespaceContext();

            xctxt.popCurrentNodeAndExpression();
        }

        return false;
    }

    /** Set to true to get diagnostic messages about the result of
     *  match pattern testing.  */
    private static final boolean DEBUG_MATCHES = false;

    /**
     * Get the match score of the given node.
     *
     * @param xctxt XPath runtime context.
     * @param context The current source tree context node.
     *
     * @return score, one of {@link #MATCH_SCORE_NODETEST},
     * {@link #MATCH_SCORE_NONE}, {@link #MATCH_SCORE_OTHER},
     * or {@link #MATCH_SCORE_QNAME}.
     *
     * @throws javax.xml.transform.TransformerException
     */
    public double getMatchScore(XPathContext xctxt, int context) throws javax.xml.transform.TransformerException {

        xctxt.pushCurrentNode(context);
        xctxt.pushCurrentExpressionNode(context);

        try {
            XObject score = m_mainExp.execute(xctxt);

            if (DEBUG_MATCHES) {
                DTM dtm = xctxt.getDTM(context);
                System.out.println("score: " + score.num() + " for " + dtm.getNodeName(context) + " for xpath " + this.getPatternString());
            }

            return score.num();
        } finally {
            xctxt.popCurrentNode();
            xctxt.popCurrentExpressionNode();
        }

        // return XPath.MATCH_SCORE_NONE;
    }

    /**
     * Warn the user of an problem.
     *
     * @param xctxt The XPath runtime context.
     * @param sourceNode Not used.
     * @param msg An error msgkey that corresponds to one of the constants found
     *            in {@link com.sun.org.apache.xpath.internal.res.XPATHErrorResources}, which is
     *            a key for a format string.
     * @param args An array of arguments represented in the format string, which
     *             may be null.
     *
     * @throws TransformerException if the current ErrorListoner determines to
     *                              throw an exception.
     */
    public void warn(XPathContext xctxt, int sourceNode, String msg, Object[] args) throws javax.xml.transform.TransformerException {

        String fmsg = XSLMessages.createXPATHWarning(msg, args);
        ErrorListener ehandler = xctxt.getErrorListener();

        if (null != ehandler) {

            // TO DO: Need to get stylesheet Locator from here.
            ehandler.warning(new TransformerException(fmsg, (SAXSourceLocator) xctxt.getSAXLocator()));
        }
    }

    /**
     * Tell the user of an assertion error, and probably throw an
     * exception.
     *
     * @param b  If false, a runtime exception will be thrown.
     * @param msg The assertion message, which should be informative.
     *
     * @throws RuntimeException if the b argument is false.
     */
    public void assertion(boolean b, String msg) {

        if (!b) {
            String fMsg = XSLMessages.createXPATHMessage(XPATHErrorResources.ER_INCORRECT_PROGRAMMER_ASSERTION, new Object[] { msg });

            throw new RuntimeException(fMsg);
        }
    }

    /**
     * Tell the user of an error, and probably throw an
     * exception.
     *
     * @param xctxt The XPath runtime context.
     * @param sourceNode Not used.
     * @param msg An error msgkey that corresponds to one of the constants found
     *            in {@link com.sun.org.apache.xpath.internal.res.XPATHErrorResources}, which is
     *            a key for a format string.
     * @param args An array of arguments represented in the format string, which
     *             may be null.
     *
     * @throws TransformerException if the current ErrorListoner determines to
     *                              throw an exception.
     */
    public void error(XPathContext xctxt, int sourceNode, String msg, Object[] args) throws javax.xml.transform.TransformerException {

        String fmsg = XSLMessages.createXPATHMessage(msg, args);
        ErrorListener ehandler = xctxt.getErrorListener();

        if (null != ehandler) {
            ehandler.fatalError(new TransformerException(fmsg, (SAXSourceLocator) xctxt.getSAXLocator()));
        } else {
            SourceLocator slocator = xctxt.getSAXLocator();
            System.out.println(fmsg + "; file " + slocator.getSystemId() + "; line " + slocator.getLineNumber() + "; column " + slocator.getColumnNumber());
        }
    }

    /**
     * This will traverse the heararchy, calling the visitor for
     * each member.  If the called visitor method returns
     * false, the subtree should not be called.
     *
     * @param owner The owner of the visitor, where that path may be
     *              rewritten if needed.
     * @param visitor The visitor whose appropriate method will be called.
     */
    public void callVisitors(ExpressionOwner owner, XPathVisitor visitor) {
        m_mainExp.callVisitors(this, visitor);
    }

    /**
     * The match score if no match is made.
     * @xsl.usage advanced
     */
    public static final double MATCH_SCORE_NONE = Double.NEGATIVE_INFINITY;

    /**
     * The match score if the pattern has the form
     * of a QName optionally preceded by an @ character.
     * @xsl.usage advanced
     */
    public static final double MATCH_SCORE_QNAME = 0.0;

    /**
     * The match score if the pattern pattern has the form NCName:*.
     * @xsl.usage advanced
     */
    public static final double MATCH_SCORE_NSWILD = -0.25;

    /**
     * The match score if the pattern consists of just a NodeTest.
     * @xsl.usage advanced
     */
    public static final double MATCH_SCORE_NODETEST = -0.5;

    /**
     * The match score if the pattern consists of something
     * other than just a NodeTest or just a qname.
     * @xsl.usage advanced
     */
    public static final double MATCH_SCORE_OTHER = 0.5;
}
